JP5319047B2 - Polycarbonate resin composition - Google Patents

Abstract

The invention aims at providing a resin composition excellent in thermal stability, light reflecting properties and hue, preferably and in flame retardance. The invention relates to a process for the production of a resin composition by blending 60 to 99.9 parts by weight of a polycarbonate resin (A) with 0.1 to 40 parts by weight of titanium dioxide pigment (B), wherein the component (B) satisfies the relationships: (i) 0.05 <= (b) - (a)<= 0.6 (wherein (a) is weight loss (wt%) observed in thermogravimetric analysis (TGA) at 23 to 100 DEG C and (b) is weight loss (wt%) observed therein at 23 to 300 DEG C) and (ii) 0.001 <= (d)/(c) <= 0.01 and 0.001 <= (e)/(c) <= 0.02 (wherein (c), (d), and (e) are contents (wt%) of Ti, Al, and Si respectively as determined by fluorescent X-ray analysis).

Description

  The present invention relates to a polycarbonate resin composition. More specifically, the present invention relates to a polycarbonate resin composition excellent in light reflectance and thermal stability of a molded product by using a specific titanium dioxide pigment.

  Polycarbonate resins have excellent transparency, heat resistance, mechanical strength, and the like, and thus are widely used in electrical, mechanical, automotive, and medical applications. Furthermore, there is a resin composition that is highly filled with a white pigment typified by a titanium dioxide pigment and excellent in light reflectivity. Molded articles made of the resin composition are used in backlight reflectors for liquid crystal display devices, reflectors for illuminated push switches and photoelectric switches, display internal frames for vending machines, and strobe reflectors.

  In such a resin composition, not only performance such as high brightness and high white hue, but also severe molding conditions (for example, higher injection speed and higher molding temperature) to cope with thinness and downsizing of molded products. Etc.) is required. That is, it is required that defective phenomena such as yellowing and silver streak due to thermal deterioration during molding do not occur even under such severe molding conditions. Such yellowing reduces light reflection characteristics, and it is assumed that silver streaks are not present in the molded product in the first place. In order to suppress such a defective phenomenon (that is, to improve thermal stability), a stabilizer such as an antioxidant may be further added. However, the blending of such a stabilizer is not always effective depending on the amount of titanium dioxide pigment added. Therefore, another method for improving the thermal stability has been demanded.

  Furthermore, the light reflecting material is often required to have flame retardancy. In addition, in recent years, it is often required not to use brominated flame retardants or phosphorus-based flame retardants as flame retardants in the field of electronic and electrical equipment for the purpose of reducing environmental impact. Therefore, the polycarbonate resin composition in which the titanium dioxide pigment is blended does not use a brominated flame retardant or a phosphorus based flame retardant while having the above excellent thermal stability and light reflectivity, and more preferably having such characteristics. Therefore, it is required to have good flame retardancy.

  It is known that aluminum oxide and organosiloxane are used as surface treatment agents as a heat stabilizing formulation for titanium dioxide pigment (see Patent Document 1). Further, it is known that silver streak can be reduced by using a titanium dioxide pigment having an aluminum oxide content of 0.1 to 2% by weight as a surface treating agent in an engineering plastic such as polyphenylene ether resin. Yes (see Patent Document 2).

  A resin composition comprising an aromatic polycarbonate resin, an alkali metal perfluoroalkanesulfonic acid, and a titanium dioxide pigment is known (see Patent Document 3). Such a document discloses a flame-retardant thermoplastic resin composition that is excellent in light reflectivity, has a low environmental load without blending a bromine compound, and is excellent in heat resistance. In addition to this patent document, a resin composition comprising an aromatic polycarbonate resin, an alkali metal perfluoroalkanesulfonic acid, and a titanium dioxide pigment is disclosed and known (see Patent Documents 4 to 7).

Japanese Patent Publication No. 60-3430 Japanese Patent Laid-Open No. 11-60743 JP 2003-183491 A JP 2002-372609 A JP 2003-226805 A JP 2003-213114 A JP 2003-342462 A

  However, the above prior art has not yet sufficiently disclosed the knowledge about a polycarbonate resin composition containing a titanium dioxide pigment having both sufficient thermal stability and hue. In particular, a polycarbonate resin composition having good flame retardancy without using a brominated flame retardant or a phosphorus flame retardant has not been known.

  In view of such circumstances, an object of the present invention is to provide a polycarbonate resin composition that is excellent in light reflection characteristics and thermal stability. More preferably, it is to provide a polycarbonate resin composition having such characteristics, which also has good flame retardancy without using a brominated flame retardant or a phosphorus flame retardant. It is a further object of the present invention to provide a light reflecting material that is formed from the resin composition and has excellent light reflecting properties and thermal stability.

  The present inventor has intensively studied to solve the above problems. As a result, it has been found that such a problem can be solved by blending a specific titanium oxide pigment with the polycarbonate resin, and the present invention has been completed.

  According to the present invention, the subject of the present invention is (1) 60 to 99.9 parts by weight of a polycarbonate resin (component A) and 0.1 to 40 parts by weight of a titanium dioxide pigment (component B), for a total of 100 parts by weight. The titanium dioxide pigment comprises: (i) a weight loss from 23 ° C. to 100 ° C. according to its thermogravimetric analysis (TGA), (a) wt%, and weight loss from 23 ° C. to 300 ° C. (B) wt%, 0.05 ≦ (b) − (a) ≦ 0.6 is satisfied, and (ii) the weight derived from the Ti element, Al element, and Si element in the fluorescent X-ray measurement When the proportions are (c) wt%, (d) wt%, and (e) wt%, respectively, 0.001 ≦ (d) / (c) ≦ 0.01 is satisfied, and 0.001 ≦ (e) / (C) Titanium dioxide pigment satisfying 0.02 Be solved by a polycarbonate resin composition characterized and.

  As described above, it is known that silver streak can be reduced by using titanium oxide having an aluminum oxide content of 0.1 to 2% by weight as a surface treating agent for an engineering plastic such as polyphenylene ether resin. Met. However, the knowledge of such a simple mixing ratio is sufficient to obtain a resin composition that is blended with a polycarbonate resin, has a good hue, has a good light reflectivity at high filling, and is excellent in thermal stability. It wasn't. The present inventor has found that by satisfying a specific weight reduction behavior and a specific component ratio, it is possible to achieve both suppression of silver streak and good hue, particularly light reflectivity during high filling, in a polycarbonate resin composition. Is. The weight reduction behavior under the condition (i) is presumed to be based on the surface adsorbed water, the crystal water derived from the surface treatment agent, and the hydration water. The weight loss at 23-100 ° C. is weakly physically adsorbed water that is in equilibrium at relative humidity in the air, and is easily desorbed during melt-kneading with the polycarbonate resin, so there is little adverse effect on the polycarbonate resin. Inferred. On the other hand, the weight loss at 100 ° C. or higher is presumed to be based on strongly adsorbed water, crystal water derived from the surface treatment agent, and hydrated water. Moisture derived from weight loss at 100 ° C. or higher tends to cause desorption at a high temperature and induce the decomposition of the polycarbonate resin. Such decomposition is considered to cause silver streak during molding.

On the other hand, the weight ratio of the elements quantified by the fluorescent X-ray measurement under the condition (ii) defines an appropriate amount range of the aluminum compound or the silicone compound. These compounds together becomes part occupied chemical adsorbed water has the function to stabilize the active sites of TiO ₂ by covering the surface of TiO _2. Therefore, if the surface coating with these compounds is too small, the hue of the resin composition is deteriorated, and particularly when the filling is high, the light reflectance is lowered. On the other hand, when it is too large, the above condition (i) is hardly satisfied and the thermal stability is low. It begins to decline. The titanium dioxide pigment of the present invention has both the hue and the thermal stability, and the characteristics of the pigment are specified using a rational and easy-to-measure index.

  One of the preferred embodiments of the present invention is that (2) an alkali (earth) metal salt (component C) of 0.0001 to 2 parts by weight based on a total of 100 parts by weight of component A and component B It is a polycarbonate resin composition of the said structure (1) containing. Also, one of the preferred embodiments of the present invention is (3) 0.05 to 1 part by weight of a fluorine-containing polymer (D component) further having a fibril-forming ability, based on 100 parts by weight of the total of the A component and the B component. It is a polycarbonate resin composition of the said structure (1)-(2) containing.

  As described above, a resin composition containing a titanium dioxide pigment, particularly a resin composition containing a high filling amount, has a good hue and thermal stability, and more preferably has such characteristics while having a bromine-based flame retardant or phosphorus. It has been required to have good flame retardancy without using a flame retardant. The combination of the titanium dioxide pigment of the present invention with an alkali (earth) sulfonate metal salt (component C) and / or a fluorinated polymer (component D) having a fibril-forming ability satisfies this requirement. It was found to be. The titanium dioxide pigment of the present invention is excellent in that it can satisfy such characteristics.

One of the preferred embodiments of the present invention is the above-mentioned constitution (1) to (4) in which A component is 70 to 90 parts by weight and B component is 10 to 30 parts by weight in a total of 100 parts by weight of component A and component B. It is a polycarbonate resin composition of (3). Such a polycarbonate resin composition has particularly good light reflection characteristics, light shielding properties, light resistance, and the like, and effectively functions as a light reflection material for various light sources.
Moreover, one of the suitable aspects of this invention is (5) the light reflection material formed from the polycarbonate resin composition of the said structure (4).
Hereinafter, each component of the present invention will be described.

<About component A>
The component A in the polycarbonate resin composition of the present invention is a polycarbonate resin that is a main component of the resin composition. A typical polycarbonate resin (hereinafter sometimes simply referred to as “polycarbonate”) is obtained by reacting a dihydric phenol and a carbonate precursor. The reaction may be performed by an interfacial polycondensation method, a molten ester, or the like. Examples thereof include an exchange method, a solid phase transesterification method of a carbonate prepolymer, and a ring-opening polymerization method of a cyclic carbonate compound.

  Specific examples of the dihydric phenol include hydroquinone, resorcinol, 4,4′-biphenol, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as “bisphenol”). A ″), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) pentane, 4, 4 ′-(p-phenylenediisopropylidene) diphenol, 4,4 ′-(m-phenylenediisopropylidene) Phenol, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, bis (4- Hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ester, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, bis (3,5-dibromo- 4-hydroxyphenyl) sulfone, bis (4-hydroxy-3-methylphenyl) sulfide, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, etc. Is mentioned. Among these, bis (4-hydroxyphenyl) alkane, especially bisphenol A (hereinafter sometimes abbreviated as “BPA”) is widely used.

  In the present invention, in addition to the general-purpose polycarbonate bisphenol A-based polycarbonate, a special polycarbonate produced using other dihydric phenols can be used as the A component.

  For example, as part or all of the dihydric phenol component, 4,4 ′-(m-phenylenediisopropylidene) diphenol (hereinafter sometimes abbreviated as “BPM”), 1,1-bis (4-hydroxy Phenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as “Bis-TMC”), 9,9-bis (4-hydroxyphenyl) Polycarbonate (homopolymer or copolymer) using fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene (hereinafter sometimes abbreviated as “BCF”) has dimensions due to water absorption. It is suitable for applications where the demands for change and shape stability are particularly severe. These dihydric phenols other than BPA are preferably used in an amount of 5 mol% or more, particularly 10 mol% or more of the entire dihydric phenol component constituting the polycarbonate.

In particular, when high rigidity and better hydrolysis resistance are required, it is particularly preferable that the component A constituting the resin composition is a copolymerized polycarbonate of the following (1) to (3). is there.
(1) BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, more preferably 45 to 65 mol%) in 100 mol% of the dihydric phenol component constituting the polycarbonate, and BCF Of 20 to 80 mol% (more preferably 25 to 60 mol%, more preferably 35 to 55 mol%).
(2) BPA is 10 to 95 mol% (more preferably 50 to 90 mol%, more preferably 60 to 85 mol%) in 100 mol% of the dihydric phenol component constituting the polycarbonate, and BCF Is 5 to 90 mol% (more preferably 10 to 50 mol%, more preferably 15 to 40 mol%).
(3) BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, more preferably 45 to 65 mol%) in 100 mol% of the dihydric phenol component constituting the polycarbonate, and Bis -Copolymer polycarbonate in which TMC is 20 to 80 mol% (more preferably 25 to 60 mol%, still more preferably 35 to 55 mol%).

  These special polycarbonates may be used alone or in combination of two or more. Moreover, these can also be mixed and used for the bisphenol A type polycarbonate generally used.

  The production method and characteristics of these special polycarbonates are described in detail in, for example, JP-A-6-172508, JP-A-8-27370, JP-A-2001-55435, and JP-A-2002-117580. ing.

Of the various polycarbonates described above, those having a water absorption and Tg (glass transition temperature) adjusted within the following ranges by adjusting the copolymer composition, etc. have good hydrolysis resistance of the polymer itself, and Since it is remarkably excellent in low warpage after molding, it is particularly suitable in a field where form stability is required.
(I) polycarbonate having a water absorption of 0.05 to 0.15%, preferably 0.06 to 0.13% and Tg of 120 to 180 ° C, or (ii) Tg of 160 to 250 ° C, Polycarbonate which is preferably 170 to 230 ° C. and has a water absorption of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

  Here, the water absorption of the polycarbonate is a value obtained by measuring the moisture content after being immersed in water at 23 ° C. for 24 hours in accordance with ISO 62-1980 using a disc-shaped test piece having a diameter of 45 mm and a thickness of 3.0 mm. is there. Moreover, Tg (glass transition temperature) is a value calculated | required by the differential scanning calorimeter (DSC) measurement based on JISK7121.

  On the other hand, carbonyl halide, carbonate ester, haloformate, or the like is used as the carbonate precursor, and specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.

  In producing a polycarbonate from such a dihydric phenol and a carbonate precursor by an interfacial polymerization method, a catalyst, a terminal terminator, and an antioxidant for preventing the dihydric phenol from being oxidized as necessary. Etc. may be used. The polycarbonate may be a branched polycarbonate copolymerized with a trifunctional or higher polyfunctional aromatic compound. Examples of the trifunctional or higher polyfunctional aromatic compound used here include 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dimethyl-4-hydroxy). Phenyl) ethane and the like.

  The structural unit derived from the polyfunctional aromatic compound in the branched polycarbonate resin is 0 in a total of 100 mol% of the structural unit derived from the dihydric phenol and the structural unit derived from the polyfunctional aromatic compound. 0.03 to 1 mol%, preferably 0.07 to 0.7 mol%, particularly preferably 0.1 to 0.4 mol%.

Further, such a branched structural unit is not only derived from a polyfunctional aromatic compound but also derived without using a polyfunctional aromatic compound, such as a side reaction during a melt transesterification reaction. Also good. The ratio of such a branched structure can be calculated by ¹ H-NMR measurement.

  Further, the polycarbonate of the present invention is a polyester carbonate obtained by copolymerizing an aromatic or aliphatic (including alicyclic) bifunctional carboxylic acid, and a copolymer obtained by copolymerizing a bifunctional alcohol (including alicyclic). Polycarbonate and polyester carbonate obtained by copolymerizing such a bifunctional carboxylic acid and a bifunctional alcohol may also be used. Moreover, the mixture which blended 2 or more types of the obtained polycarbonate may be used.

  The aliphatic bifunctional carboxylic acid used here is preferably an α, ω-dicarboxylic acid. Examples of the aliphatic bifunctional carboxylic acid include, for example, sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, icosanedioic acid and the like, and saturated aliphatic dicarboxylic acid and cyclohexanedicarboxylic acid. Preferred are alicyclic dicarboxylic acids such as As the bifunctional alcohol, an alicyclic diol is more preferable, and examples thereof include cyclohexanedimethanol, cyclohexanediol, and tricyclodecane dimethanol.

Furthermore, in the present invention, a polycarbonate-polyorganosiloxane copolymer obtained by copolymerizing polyorganosiloxane units can be used as the component A.
The component A polycarbonate may be a mixture of two or more of the above-mentioned polycarbonates having different dihydric phenols, polycarbonates containing branched components, polyester carbonates, polycarbonate-polyorganosiloxane copolymers and the like. . Furthermore, what mixed 2 or more types of polycarbonates from which a manufacturing method differs, a polycarbonate from which a terminal terminator differs, etc. can also be used.

  In the polycarbonate polymerization reaction, the reaction by the interfacial polycondensation method is usually a reaction between a dihydric phenol and phosgene, and is carried out in the presence of an acid binder and an organic solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the organic solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. In order to accelerate the reaction, for example, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide, or tetra-n-butylphosphonium bromide, a quaternary ammonium compound, or a quaternary phosphonium compound can be used. . At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

  In such a polymerization reaction, a terminal terminator is usually used. Monofunctional phenols can be used as such end terminators. As monofunctional phenols, for example, monofunctional phenols such as phenol, p-tert-butylphenol, and p-cumylphenol are preferably used. Furthermore, as monofunctional phenols, long chain alkyl groups having 10 or more carbon atoms such as decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, eicosylphenol, docosylphenol and triacontylphenol. A monofunctional phenol substituted with a nucleus can be mentioned, and the phenol is effective in improving fluidity and hydrolysis resistance. Such end terminators may be used alone or in combination of two or more.

The reaction by the melt transesterification method is usually a transesterification reaction between a dihydric phenol and a carbonate ester, and the alcohol or alcohol produced by mixing the dihydric phenol and the carbonate ester with heating in the presence of an inert gas. It is carried out by a method of distilling phenol. The reaction temperature varies depending on the boiling point of the alcohol or phenol produced, but in most cases is in the range of 120 to 350 ° C. In the latter stage of the reaction, the reaction system is decompressed to about 1.33 × 10 ^{3 to} 13.3 Pa to facilitate the distillation of the alcohol or phenol produced. The reaction time is usually about 1 to 4 hours.

  Examples of the carbonate ester include esters such as an aryl group having 6 to 10 carbon atoms, an aralkyl group, or an alkyl group having 1 to 4 carbon atoms which may have a substituent. Among them, diphenyl carbonate is preferable.

A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include alkali metal compounds such as sodium hydroxide, potassium hydroxide, sodium salt and potassium salt of dihydric phenol; alkaline earth metal compounds such as calcium hydroxide, barium hydroxide and magnesium hydroxide; Nitrogen-containing basic compounds such as methylammonium hydroxide, tetraethylammonium hydroxide, trimethylamine, and triethylamine can be used. Further, alkali (earth) metal alkoxides, alkali (earth) metal organic acid salts, boron compounds, germanium compounds, antimony compounds, titanium compounds, zirconium compounds, etc., esterification reaction, transesterification The catalyst used for the reaction can be used. These catalysts may be used alone or in combination of two or more. The amount of the catalyst used is preferably selected in the range of 1 × 10 ⁻⁹ to 1 × 10 ⁻⁵ equivalents, more preferably 1 × 10 ^{−8 to} 5 × 10 ⁻⁶ equivalents, relative to 1 mol of dihydric phenol as a raw material. It is.

  In the reaction by the melt transesterification method, for example, 2-chlorophenylphenyl carbonate, 2-methoxycarbonylphenylphenyl carbonate, 2-ethoxycarbonyl is used at the later stage or after completion of the polycondensation reaction for the purpose of reducing the phenolic end groups of the produced polycarbonate. Compounds such as phenylphenyl carbonate can be added.

  Furthermore, it is preferable to use a deactivator that neutralizes the activity of the catalyst in the melt transesterification method. The amount of the deactivator is preferably 0.5 to 50 mol with respect to 1 mol of the remaining catalyst. Moreover, it is suitable to use in the ratio of 0.01-500 ppm with respect to the polycarbonate after superposition | polymerization, More preferably, it is 0.01-300 ppm, Most preferably, it is a ratio of 0.01-100 ppm. Examples of preferable quenching agents include phosphonium salts such as tetrabutylphosphonium dodecylbenzenesulfonate and ammonium salts such as tetraethylammonium dodecylbenzyl sulfate.

  The viscosity average molecular weight of the polycarbonate resin of component A is not limited. However, when the viscosity average molecular weight is less than 10,000, the strength and the like are lowered, and when it exceeds 50,000, the molding process characteristics are lowered. Therefore, the range of 10,000 to 50,000 is preferable. The range of 15,000 to 30,000 is more preferable, and the range of 15,000 to 28,000 is more preferable. In this case, it is also possible to mix a polycarbonate having a viscosity average molecular weight outside the above range within a range in which moldability and the like are maintained. For example, a high molecular weight polycarbonate component having a viscosity average molecular weight exceeding 50,000 can be blended.

The viscosity average molecular weight referred to in the present invention is first determined by using an Ostwald viscometer from a solution in which 0.7 g of aromatic polycarbonate is dissolved in 100 ml of methylene chloride at 20 ° C. with a specific viscosity (η _SP ) calculated by the following formula. ,
Specific viscosity (η _SP ) = (t−t ₀ ) / t ₀
[T ₀ is methylene chloride falling seconds, t is sample solution falling seconds]
The viscosity average molecular weight M is calculated from the determined specific viscosity (η _SP ) by the following formula.
η _SP /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
c = 0.7

  In addition, calculation of the viscosity average molecular weight in the polycarbonate resin composition of this invention is performed in the following way. That is, the composition is mixed with 20 to 30 times its weight of methylene chloride to dissolve the soluble component in the composition. Such soluble matter is collected by Celite filtration. Thereafter, the solvent in the obtained solution is removed. The solid after removal of the solvent is sufficiently dried to obtain a solid component that dissolves in methylene chloride. A specific viscosity at 20 ° C. is determined from a solution obtained by dissolving 0.7 g of the solid in 100 ml of methylene chloride in the same manner as described above, and the viscosity average molecular weight M is calculated from the specific viscosity in the same manner as described above.

<About B component>
The component B of the present invention is (i) weight loss at 23 ° C. to 100 ° C. by thermogravimetric analysis (TGA) is (a) wt%, and weight loss at 23 ° C. to 300 ° C. is (b) wt%. When satisfying 0.05 ≦ (b) − (a) ≦ 0.6, (ii) weight ratios derived from Ti element, Al element, and Si element in the fluorescent X-ray measurement are (c), ( When d) and (e), 0.001 ≦ (d) / (c) ≦ 0.01 is satisfied, and 0.001 ≦ (e) / (c) ≦ 0.02 is satisfied.

  The lower limit of the value of (b)-(a) is more preferably 0.15, and the upper limit of this value is more preferably 0.3. The lower limit of the above (d) / (c) is more preferably 0.003, and the upper limit thereof is more preferably 0.01. The lower limit of (e) / (c) is more preferably 0.005, and the upper limit is more preferably 0.015.

  In the titanium dioxide pigment satisfying the above (i) and (ii), one satisfying at least one of the following formulas, specifically, (b)-(a) exceeds 0.6 or (d) / (c) is 0 A titanium dioxide pigment that exceeds 0.01 or (e) / (c) exceeds 0.02 has a decomposition action on the polycarbonate resin, and tends to make the thermal stability of the resin composition insufficient. The titanium dioxide pigment in which (b)-(a) is less than 0.05, or (d) / (c) or (e) / (c) is less than 0.001, It tends to reduce the hue of the resin composition and particularly the light reflection characteristics at the time of high filling.

  Note that the thermogravimetric analysis (TGA) measurement under the above condition (i) is performed under the TGA measurement device under the measurement conditions in which the temperature is increased from 23 ° C. in a nitrogen gas atmosphere to 900 ° C. at a temperature increase rate of 20 ° C./min. . The operation of calculating the weight ratio of the element from the fluorescent X-ray measurement in the above condition (ii) can be calculated based on the calibration line calculated from the element weight and the peak intensity usually obtained from the standard of each element. . In recent years, a quantifiable program is incorporated in the fluorescent X-ray measurement apparatus, and the weight ratio of the element can be obtained directly from the apparatus. Examples of the apparatus include MESA-500 type manufactured by Horiba, Ltd., and can be suitably used for calculating the weight ratio of elements. Such calculation is performed by the basic parameter method in the MESA-500 type.

The titanium oxide used in the present invention may be either anatase type or rutile type in crystal form, and these may be used as a mixture as required. A rutile type is more preferable in terms of initial mechanical properties and long-term weather resistance. A rutile type crystal may contain an anatase type crystal. Further, as a method for producing TiO ₂ , products produced by a sulfuric acid method, a chlorine method, and various other methods can be used, but the chlorine method is more preferable. The titanium oxide of the present invention is not particularly limited in shape, but is preferably in the form of particles. The average particle diameter of titanium oxide is preferably 0.01 to 0.4 μm, more preferably 0.1 to 0.3 μm, and still more preferably 0.15 to 0.25 μm. Such an average particle diameter is calculated by measuring the number of individual single particles and observing the number average thereof through observation with an electron microscope. The coating with various metal oxides on the surface of TiO ₂ can be performed by various commonly used methods. For example, it is manufactured from the following steps 1) to 8). That is, 1) untreated TiO ₂ after dry pulverization is made into an aqueous slurry, 2) the slurry is wet pulverized and atomized, 3) a fine particle slurry is collected, and 4) a metal salt is soluble in the fine particle slurry. Add compound 5) Neutralize and coat TiO ₂ surface with metal hydrated oxide 6) Remove by-products, adjust slurry pH, filter, and clean with pure water 7) Washed A method of drying the cake, and 8) crushing the dried product with a jet mill or the like. In addition to this method, for example, a method of reacting TiO ₂ particles with an active metal compound in a gas phase can be mentioned. Further, in the coating of the metal oxide surface treatment agent on the TiO ₂ surface, firing after the surface treatment, surface treatment again after the surface treatment, and firing after the surface treatment and surface treatment again are performed. Is possible. As the surface treatment with the metal oxide, either a high-density treatment or a low-density (porous) treatment can be selected.

The conditions (i) and (ii) can be adjusted by adjusting the metal oxide for the surface treatment and the conditions for the firing treatment. The titanium dioxide pigment of the present invention is surface-treated with aluminum oxide and silicon oxide as apparent from such conditions. These may be surface-treated in any order or as a mixture, but are preferably treated with silicon oxide after aluminum oxide treatment. The titanium dioxide pigment of the present invention may include a surface treatment with other metal oxides. Examples of such metals include titanium, zirconium, antimony, tin, and zinc. The metal oxide component for these surface treatments, some may be a mode which is present inside the TiO ₂ particles.

  Further, the B component titanium dioxide pigment is more preferably surface-treated with an organic compound. As such a surface treatment agent, various treatment agents such as polyol, amine, and silicone can be used. Examples of the polyol-based surface treatment agent include pentaerythritol, trimethylolethane, and trimethylolpropane. Examples of the amine-based surface treatment agent include triethanolamine acetate and trimethylolamine acetate. Examples of the silicone-based surface treatment agent include halogen-substituted organosilicon compounds and organosilicon compounds containing alkoxy groups and / or Si—H groups, and the latter organosilicon compounds are particularly preferred. Examples of the halogen-substituted organosilicon compound include alkylchlorosilane, and examples of the organosilicon compound containing an alkoxy group and / or Si—H group include alkylalkoxysilane, alkylalkoxysiloxane, and alkylhydrogensiloxane.

  In such silane compounds and siloxane compounds, a part of the alkyl groups may be substituted with phenyl groups, but those having no phenyl group substitution are more preferable. Such an alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms. The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, and particularly preferably a methoxy group.

  The alkylalkoxysilane compound may contain any of 1 to 3 alkoxy groups, or may be a mixture thereof, preferably 2 to 3 alkoxy groups, particularly preferably 3 alkoxy groups. . Specific examples of the alkylalkoxysilane compound include, for example, methyltrimethoxysilane, ethyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, methyloctyldimethoxysilane, decyltrimethoxysilane, and octadecyltrimethoxysilane. Is done.

  The content ratio of the alkoxy group and the Si—H group in the siloxane compound is preferably in the range of 0.1 to 1.2 mol / 100 g, more preferably in the range of 0.12 to 1 mol / 100 g, and 0.15 to 0.6 mol / A range of 100 g is more preferable. Such a ratio can be determined by measuring the amount of hydrogen or alcohol generated per unit weight of the siloxane compound by an alkali decomposition method.

In general, the structure of a siloxane compound is constituted by arbitrarily combining the following four types of siloxane units. That is,
M units: (CH ₃ ) ₃ SiO _1/2 , H (CH ₃ ) ₂ SiO _1/2 , H ₂ (CH ₃ ) SiO _1/2 , (CH ₃ ) ₂ (CH ₂ = CH) SiO _1/2 Monofunctional siloxane units such as (CH ₃ ) ₂ (C ₆ H ₅ ) SiO _1/2 , (CH ₃ ) (C ₆ H ₅ ) (CH ₂ ═CH) SiO _1/2 ,
D unit: (CH ₃ ) ₂ SiO, H (CH ₃ ) SiO, H ₂ SiO, H (C ₆ H ₅ ) SiO, (CH ₃ ) (CH ₂ ═CH) SiO, (C ₆ H ₅ ) ₂ SiO Bifunctional siloxane units such as
T unit: (CH ₃ ) SiO _3/2 , (C ₃ H ₇ ) SiO _3/2 , HSiO _3/2 , (CH ₂ ═CH) SiO _3/2 , (C ₆ H ₅ ) SiO _3/2 etc. A trifunctional siloxane unit of
Q unit: a tetrafunctional siloxane unit represented by SiO ₂ .

Specifically, the structure of the siloxane compound is expressed as D _n , T _p , M _m D _n , M _m T _p , M _m Q _q , M _m D _n T _p , M _m D _n Q _{q , M m T p Q q,} M m D n T p Q q, D n T p, D n Q q, include _{D n} T p _{Q q.} Among these, preferable structures of the silicone compound are M _m D _n , M _m T _p , M _m D _n T _p , and M _m D _n Q _q , and more preferable structures are M _m D _n or M _m D _n. T _p .

  Here, the coefficients m, n, p, and q in the above formula are integers of 1 or more that indicate the degree of polymerization of each siloxane unit, and the sum of the coefficients in each formula represents the average degree of polymerization of the siloxane compound. . This average degree of polymerization is preferably in the range of 2-150, more preferably in the range of 3-80. Moreover, when any of m, n, p, and q is a numerical value of 2 or more, it can be set as 2 or more types of siloxane units from which the hydrogen atom couple | bonded and an organic residue differ.

  The amount of the organic compound to be surface-treated is preferably 1% by weight or less, more preferably 0.6% by weight or less per 100% by weight of the B component. On the other hand, the lower limit is 0.05% by weight or more. The titanium dioxide pigment surface-treated with an organosilicon compound containing an alkoxy group and / or Si—H group gives good light reflectivity to the resin composition of the present invention.

<About the content of each component>
The polycarbonate resin composition of the present invention is 60 to 99.9 parts by weight, preferably 70 to 95 parts by weight, more preferably 75 to 90 parts by weight, still more preferably, per 100 parts by weight of the total of component A and component B. It comprises 75 to 85 parts by weight of component A and 0.1 to 40 parts by weight, preferably 5 to 30 parts by weight, more preferably 10 to 25 parts by weight, and even more preferably 15 to 25 parts by weight. The polycarbonate resin composition of this invention can be manufactured by mix | blending B component with A component in this ratio. If the B component is less than the lower limit, it is difficult to clarify the effect of improving the heat stability and it is difficult to obtain a good light reflection effect. On the other hand, if the B component exceeds the upper limit and is too much, the heat of the resin composition The stability may be lowered and the physical properties may be lowered.

<About component C>
The alkali (earth) metal sulfonate in the present invention is a metal salt of fluorine-substituted alkyl sulfonic acid such as a metal salt of perfluoroalkyl sulfonic acid and alkali metal or alkaline earth metal, and aromatic sulfonic acid and alkali metal. Or a metal salt with an alkaline earth metal salt.

  Examples of the alkali metal constituting the metal salt of the present invention include lithium, sodium, potassium, rubidium and cesium, and examples of the alkaline earth metal include beryllium, magnesium, calcium, strontium and barium. More preferred is an alkali metal. Among such alkali metals, rubidium and cesium having larger ionic radii are suitable when the requirement for transparency is higher, but these are not general-purpose and difficult to purify, resulting in cost. It may be disadvantageous. On the other hand, metals with smaller ionic radii such as lithium and sodium may be disadvantageous in terms of flame retardancy. Considering these, the alkali metal in the sulfonic acid alkali metal salt can be properly used. In any respect, the sulfonic acid potassium salt having an excellent balance of properties is most preferable. Such potassium salts and sulfonic acid alkali metal salts comprising other alkali metals can be used in combination.

  Specific examples of alkali metal perfluoroalkyl sulfonates include potassium trifluoromethane sulfonate, potassium perfluorobutane sulfonate, potassium perfluorohexane sulfonate, potassium perfluorooctane sulfonate, sodium pentafluoroethane sulfonate, perfluoro Sodium butanesulfonate, sodium perfluorooctanesulfonate, lithium trifluoromethanesulfonate, lithium perfluorobutanesulfonate, lithium perfluoroheptanesulfonate, cesium trifluoromethanesulfonate, cesium perfluorobutanesulfonate, perfluorooctanesulfonate Cesium, cesium perfluorohexane sulfonate, rubidium perfluorobutane sulfonate, and perf Oro hexane sulfonate rubidium, and these may be used in combination of at least one or two. Here, the carbon number of the perfluoroalkyl group is preferably in the range of 1-18, more preferably in the range of 1-10, and still more preferably in the range of 1-8. Of these, potassium perfluorobutanesulfonate is particularly preferred.

The alkali (earth) metal salt of perfluoroalkylsulfonic acid composed of an alkali metal is usually mixed with not less than fluoride ions (F ⁻ ). The presence of such fluoride ions can be a factor that lowers the flame retardancy, so it is preferably reduced as much as possible. The ratio of such fluoride ions can be measured by ion chromatography. The content of fluoride ions is preferably 100 ppm or less, more preferably 40 ppm or less, and particularly preferably 10 ppm or less. Moreover, it is suitable that it is 0.2 ppm or more in terms of production efficiency. Such alkali (earth) metal salt of perfluoroalkylsulfonic acid having a reduced amount of fluoride ion is contained in a raw material when producing a fluorine-containing organometallic salt using a known production method. A method for reducing the amount of fluoride ions, a method for removing hydrogen fluoride and the like obtained by the reaction by a gas generated during the reaction or heating, and a purification method such as recrystallization and reprecipitation for producing a fluorine-containing organometallic salt Can be produced by a method of reducing the amount of fluoride ions using, for example. In particular, since the B component is relatively soluble in water, ion-exchanged water, particularly water having an electric resistance of 18 MΩ · cm or more, that is, an electric conductivity of about 0.55 μS / cm or less, and from room temperature is used. It is preferable to produce by a process of dissolving at high temperature and washing, then cooling and recrystallization.

  Specific examples of the aromatic (earth) metal salt of an aromatic sulfonate include, for example, disodium diphenyl sulfide-4,4′-disulfonate, dipotassium diphenyl sulfide-4,4′-disulfonate, potassium 5-sulfoisophthalate, Sodium 5-sulfoisophthalate, polysodium polyethylene terephthalate polysulfonate, calcium 1-methoxynaphthalene-4-sulfonate, disodium 4-dodecylphenyl ether disulfonate, polysodium poly (2,6-dimethylphenylene oxide) polysulfonate Poly (1,3-phenylene oxide) polysulfonic acid polysodium, poly (1,4-phenylene oxide) polysulfonic acid polysodium, poly (2,6-diphenylphenylene oxide) polysulfonic acid poly Lithium, poly (2-fluoro-6-butylphenylene oxide) polysulfonate, potassium sulfonate of benzenesulfonate, sodium benzenesulfonate, strontium benzenesulfonate, magnesium benzenesulfonate, dipotassium p-benzenedisulfonate, naphthalene-2 , 6-disulfonic acid dipotassium, biphenyl-3,3'-disulfonic acid calcium, diphenylsulfone-3-sulfonic acid sodium, diphenylsulfone-3-sulfonic acid potassium, diphenylsulfone-3,3'-disulfonic acid dipotassium, diphenylsulfone -3,4'-dipotassium disulfonate, α, α, α-trifluoroacetophenone-4-sodium sulfonate, dipotassium benzophenone-3,3'-disulfonate, thiof -2,5-disulfonic acid disodium, thiophene-2,5-disulfonic acid dipotassium, thiophene-2,5-disulfonic acid calcium, benzothiophene sodium sulfonate, diphenyl sulfoxide-4- potassium sulfonate, naphthalene sulfone Examples thereof include a formalin condensate of sodium acid and a formalin condensate of sodium anthracene sulfonate. Among these aromatic sulfonate alkali (earth) metal salts, potassium salts are particularly preferable. Among these aromatic sulfonate alkali (earth) metal salts, potassium diphenylsulfone-3-sulfonate and dipotassium diphenylsulfone-3,3′-disulfonate are preferable, and particularly a mixture thereof (the former and the latter). Is preferably 15/85 to 30/70).

<About D component>
Examples of the anti-dripping agent in the present invention include a fluorinated polymer having a fibril-forming ability. Examples of such a polymer include polytetrafluoroethylene and tetrafluoroethylene copolymers (for example, tetrafluoroethylene / hexafluoropropylene copolymer). Polymer, etc.), partially fluorinated polymers as shown in US Pat. No. 4,379,910, polycarbonate resins produced from fluorinated diphenols, and the like, preferably polytetrafluoroethylene (hereinafter referred to as PTFE). May be called).

Polytetrafluoroethylene (fibrillated PTFE) having fibril-forming ability has a very high molecular weight, and exhibits a tendency to bind PTFE to each other by an external action such as shearing force to form a fiber. Its number average molecular weight ranges from 1.5 million to tens of millions. The lower limit is more preferably 3 million. The number average molecular weight is calculated based on the melt viscosity of polytetrafluoroethylene at 380 ° C. as disclosed in JP-A-6-145520. That is, the fibrillated PTFE has a melt viscosity at 380 ° C. measured by the method described in this publication in the range of 10 ⁷ to 10 ¹³ poise, preferably in the range of 10 ⁸ to 10 ¹² poise.

  Such PTFE can be used in solid form or in the form of an aqueous dispersion. In addition, PTFE having such fibril-forming ability can improve the dispersibility in the resin, and it is also possible to use a PTFE mixture in a mixed form with other resins in order to obtain better flame retardancy and mechanical properties. is there. Further, as disclosed in JP-A-6-145520, those having a structure having such a fibrillated PTFE as a core and a low molecular weight polytetrafluoroethylene as a shell are also preferably used.

  Examples of such commercially available fibrillated PTFE include Teflon (registered trademark) 6J from Mitsui DuPont Fluorochemical Co., Ltd., Polyflon MPA FA500, F-201L from Daikin Chemical Industries, Ltd., and the like. Commercially available aqueous dispersions of fibrillated PTFE include: Fluon AD-1, AD-936 manufactured by Asahi IC Fluoropolymers, Fluon D-1, D-2 manufactured by Daikin Industries, Ltd., Mitsui A representative example is Teflon (registered trademark) 30J manufactured by DuPont Fluorochemical Co., Ltd.

  As a mixed form of fibrillated PTFE, (1) a method in which an aqueous dispersion of fibrillated PTFE and an aqueous dispersion or solution of an organic polymer are mixed and co-precipitated to obtain a co-agglomerated mixture (JP-A-60-258263). (2) A method of mixing an aqueous dispersion of fibrillated PTFE and dried organic polymer particles (Japanese Patent Laid-Open No. 4-272957). Described method), (3) A method in which an aqueous dispersion of fibrillated PTFE and an organic polymer particle solution are uniformly mixed, and the respective media are simultaneously removed from the mixture (Japanese Patent Laid-Open Nos. 06-220210, (Method described in Japanese Patent Application Laid-Open No. 08-188653), (4) A method of polymerizing monomers forming an organic polymer in an aqueous dispersion of fibrillated PTFE (Method described in JP-A-9-95583), and (5) an aqueous dispersion of PTFE and an organic polymer dispersion are uniformly mixed, and then a vinyl monomer is further polymerized in the mixed dispersion. Thereafter, those obtained by a method for obtaining a mixture (a method described in JP-A-11-29679, etc.) can be used. Examples of commercially available fibrillated PTFE in a mixed form include “Metablene A3800” (trade name) manufactured by Mitsubishi Rayon Co., Ltd. and “BLENDEX B449” (trade name) manufactured by GE Specialty Chemicals.

  The polycarbonate resin composition of the present invention may require high surface smoothness. Therefore, the fibrillated PTFE is preferably finely dispersed. As a means of achieving such fine dispersion, the mixed form of fibrillated PTFE is advantageous. A method of directly supplying an aqueous dispersion in a melt kneader is also advantageous for fine dispersion. However, in the case of the aqueous dispersion form, consideration is required in that the hue is slightly deteriorated. The proportion of fibrillated PTFE in the mixed form is preferably 10 to 80% by weight, more preferably 15 to 75% by weight, in 100% by weight of the mixture. When the ratio of fibrillated PTFE is in such a range, good dispersibility of fibrillated PTFE can be achieved.

  The amount of component C is preferably 0.0001 to 2 parts by weight, more preferably 0.001 to 0.6 parts by weight, and still more preferably 0.005 based on the total of 100 parts by weight of component A and component B. -0.2 parts by weight. The blending amount of component D is 0.05 to 1 part by weight, preferably 0.1 to 0.8 part by weight, more preferably 0.15 to 0. 0, based on a total of 100 parts by weight of component A and component B. 7 parts by weight. In addition, the compounding quantity of D component refers to the net PTFE quantity in the case of PTFE of a mixed form. With such preferable contents of the C component and the D component, both good flame retardancy and thermal stability can be achieved.

<About other ingredients>
The polycarbonate resin composition of the present invention contains the component A and component B as essential components, and contains component C and / or component D, more preferably component C and component D as suitable components. In addition to these, other components can be appropriately contained as necessary.

(I) Phosphorus stabilizer It is preferable that various polycarbonate stabilizers are further blended in the polycarbonate resin composition of the present invention. The main purpose of blending such a phosphorus stabilizer is to improve the thermal stability during molding of the resin composition and to obtain good light reflectivity. Examples of such phosphorus stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and esters thereof, and tertiary phosphine.

  Specifically, as the phosphite compound, for example, triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl Phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, tris ( Diethylphenyl) phosphite, tris (di-iso-propylphenyl) phosphite, tris (di-n-butylphenyl) phosphite, tris (2,4-di-tert-butylpheny) ) Phosphite, tris (2,6-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2 , 6-Di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, bis {2,4-bis (1-methyl-1-phenylethyl) phenyl} pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dicyclohexyl pentaerythritol diphosphite, etc. And the like.

  Further, as other phosphite compounds, those which react with dihydric phenols and have a cyclic structure can be used. For example, 2,2′-methylenebis (4,6-di-tert-butylphenyl) (2,4-di-tert-butylphenyl) phosphite, 2,2′-methylenebis (4,6-di-tert- Examples include butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite, 2,2′-methylenebis (4-methyl-6-tert-butylphenyl) octyl phosphite, and the like.

  Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, And diisopropyl phosphate are exemplified, and triphenyl phosphate and trimethyl phosphate are preferable.

  Examples of the phosphonite compound include tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3′-biphenylenedi. Phosphonite, tetrakis (2,4-di-tert-butylphenyl) -3,3′-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite Tetrakis (2,6-di-tert-butylphenyl) -4,3′-biphenylene diphosphonite, tetrakis (2,6-di-tert-butylphenyl) -3,3′-biphenylene diphosphonite, bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite, bis (2,4-di tert-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-n-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-tert-butylphenyl)- 4-phenyl-phenylphosphonite, bis (2,6-di-tert-butylphenyl) -3-phenyl-phenylphosphonite, and the like, and tetrakis (di-tert-butylphenyl) -biphenylenediphosphonite, Bis (di-tert-butylphenyl) -phenyl-phenylphosphonite is preferred, tetrakis (2,4-di-tert-butylphenyl) -biphenylenediphosphonite, and bis (2,4-di-tert-butylphenyl) ) -Phenyl-phenylphosphonite is more preferred. Such a phosphonite compound is preferable because it can be used in combination with a phosphite compound having an aryl group in which two or more alkyl groups are substituted.

  Examples of the phosphonate compound include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

  Tertiary phosphine includes triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, tri-p-tolyl. Examples include phosphine, trinaphthylphosphine, and diphenylbenzylphosphine. A particularly preferred tertiary phosphine is triphenylphosphine.

  The phosphorus stabilizers can be used alone or in combination of two or more. Among the phosphorus stabilizers, phosphite compounds or phosphonite compounds are preferable. The most preferred phosphite compound is tris (2,4-di-tert-butylphenyl) phosphite. Examples of the phosphonite compound include tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite and bis (2,4-di-tert-butylphenyl) -phenyl-phenylphosphonite and these And a mixture of these is most preferable. The weight ratio between the two (the former / the latter) is preferably in the range of 90/10 to 70/30, more preferably in the range of 85/15 to 75/25. A combination of these and a phosphate compound is also a preferred embodiment.

(Ii) Hindered phenol stabilizer For the main purpose of improving the heat stability, heat aging resistance, and ultraviolet resistance during molding of the polycarbonate resin composition of the present invention, the resin composition contains a hindered phenol. A phenolic stabilizer may be blended. Examples of such hindered phenol-based stabilizers include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 -Tert-butyl-6- (3'-tert-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2,6-di-tert-butyl-4- (N, N- Dimethylaminomethyl) phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4 -Ethyl-6-tert-butylphenol), 4,4'-methylenebis (2, -Di-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'-dimethylene-bis (6-α-methyl-benzyl-p-cresol) 2,2 ' -Ethylidene-bis (4,6-di-tert-butylphenol), 2,2'-butylidene-bis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert) -Butylphenol), triethylene glycol-N-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, 1,6-hexanediol bis [3- (3,5-di- tert-butyl-4-hydroxyphenyl) propionate], bis [2-tert-butyl-4-methyl 6- (3-tert-butyl) Ru-5-methyl-2-hydroxybenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1, -Dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4'-thiobis (6-tert-butyl-m-cresol), 4,4'-thiobis (3- Methyl-6-tert-butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4 ′ -Di-thiobis (2,6-di-tert-butylphenol), 4,4'-tri-thiobis (2,6-di-tert-butylphenol), 2,2-thiodie Renbis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-tert- Butylanilino) -1,3,5-triazine, N, N′-hexamethylenebis- (3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N, N′-bis [3- (3 , 5-Di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl -2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxyphenyl) iso Cyanurate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris2 [3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate and tetrakis [methylene-3- (3,5-di-tert-butyl -4-hydroxyphenyl) propionate] methane and the like. Among these, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (CIBA SPECILITY CHEMICALS: Irganox 1076 (trade name)) is preferable as a typical commercial product. All of the above-mentioned hindered phenol antioxidants are easily available, and these can be used alone or in combination of two or more.

  The blending amount of the above (i) phosphorus stabilizer and (ii) hindered phenol antioxidant is 0.0001 to 1 part by weight, preferably 0 based on the total of 100 parts by weight of component A and component B, respectively. 0.001 to 0.1 part by weight, more preferably 0.005 to 0.1 part by weight. When the amount of the stabilizer is too much less than the above range, it is difficult to obtain a good stabilizing effect. When the amount exceeds the above range, the physical properties of the composition may be lowered.

  In the polycarbonate resin composition of the present invention, an antioxidant other than the hindered phenol antioxidant can be used in order to further stabilize the hue at the time of heat treatment of the molded product. Examples of such other antioxidants include lactone stabilizers represented by reaction products of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene (such stabilizers). Are described in JP-A-7-233160), and pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-laurylthiopropionate), and glycerol-3-stearylthio And sulfur-containing stabilizers such as propionate. The blending amount of these other antioxidants is preferably 0.001 to 0.05 parts by weight based on 100 parts by weight of the total of component A and component B. Furthermore, the polycarbonate resin composition of the present invention can also contain a hindered amine light stabilizer.

(Iii) Flame Retardant The polycarbonate resin composition of the present invention may be compounded with various compounds other than alkali (earth) metal sulfonates known as flame retardants for polycarbonate resins. Although the compounding of such a compound brings about an improvement in flame retardancy, it also brings about an improvement in fluidity, rigidity, and thermal stability, for example, based on the properties of each compound. Examples of the flame retardant include (i) an organophosphorus flame retardant (for example, a monophosphate compound, a phosphate oligomer compound, a phosphonate oligomer compound, a phosphonitrile oligomer compound, and a phosphonic acid amide compound), (ii) a silicone comprising a silicone compound. Flame retardants, (iii) halogenated flame retardants (eg brominated epoxy resins, brominated polystyrenes, brominated polycarbonates (including oligomers), brominated polyacrylates, chlorinated polyethylenes, etc.), and (iv) sulfonic acids Examples include organic metal salts other than alkali (earth) metal salts.

(Iii-i) Organophosphorus Flame Retardant As the organophosphorus flame retardant of the present invention, an aryl phosphate compound is suitable. This is because such a phosphate compound is generally excellent in hue and hardly adversely affects high light reflectivity. Moreover, since the phosphate compound has a plasticizing effect, it is advantageous in that the moldability of the resin composition of the present invention can be improved. As the phosphate compound, various phosphate compounds known as conventional flame retardants can be used, and more preferably, one or more phosphate compounds represented by the following general formula (1) can be mentioned.

（但し前記式中のＸは、二価フェノールから誘導される二価の有機基を表し、Ｒ^１１、Ｒ^１２、Ｒ^１３、およびＲ^１４はそれぞれ一価フェノールから誘導される一価の有機基を表し、ｎは０〜５の整数を表す。）

(However, X in the above formula represents a divalent organic group derived from a dihydric phenol, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each a monovalent organic group derived from a monohydric phenol. And n represents an integer of 0 to 5.)

  The phosphate compound of the above formula may be a mixture of compounds having different n numbers, in which case the average n number is preferably 0.5 to 1.5, more preferably 0.8 to 1. 2, More preferably, it is 0.95-1.15, Most preferably, it is the range of 1-1.14.

  Preferable specific examples of the dihydric phenol for deriving X include hydroquinone, resorcinol, bis (4-hydroxydiphenyl) methane, bisphenol A, dihydroxydiphenyl, dihydroxynaphthalene, bis (4-hydroxyphenyl) sulfone, bis (4 -Hydroxyphenyl) ketone and bis (4-hydroxyphenyl) sulfide are exemplified, among which resorcinol, bisphenol A, and dihydroxydiphenyl are preferable.

Preferable specific examples of the monohydric phenol for deriving R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ include phenol, cresol, xylenol, isopropylphenol, butylphenol, and p-cumylphenol. Are phenol and 2,6-dimethylphenol.

  Such a monohydric phenol may substitute a halogen atom. Specific examples of the phosphate compound having a group derived from the monohydric phenol include tris (2,4,6-tribromophenyl) phosphate and tris. Examples include (2,4-dibromophenyl) phosphate, tris (4-bromophenyl) phosphate, and the like.

  On the other hand, specific examples of phosphate compounds not substituted with halogen atoms include monophosphate compounds such as triphenyl phosphate and tri (2,6-xylyl) phosphate, and resorcinol bisdi (2,6-xylyl) phosphate). Preferred are phosphate oligomers mainly composed of phosphate oligomers, phosphate oligomers mainly composed of 4,4-dihydroxydiphenyl bis (diphenyl phosphate), and phosphate oligomers mainly composed of bisphenol A bis (diphenyl phosphate). Indicates that a small amount of other components having different degrees of polymerization may be included, and more preferably, the component of n = 1 in the formula (1) is 80% by weight or more, more preferably 85% by weight or more, and still more preferably Containing 90% by weight or more Show.).

  The compounding amount of the organic phosphorus flame retardant is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, still more preferably 2 to 7 parts by weight based on 100 parts by weight of the total of the A component and the B component. Part.

(Iii-iii) Halogen Flame Retardant As the halogen flame retardant of the present invention, brominated polycarbonate (including oligomer) is particularly suitable. The light reflecting material is often exposed to a high temperature by a light source. Therefore, brominated polycarbonate having excellent heat resistance may be required. In the brominated polycarbonate used in the present invention, the structural unit represented by the following general formula (8) is at least 60 mol%, preferably at least 80 mol%, particularly preferably substantially the following general formula. It is a brominated polycarbonate compound consisting of the structural unit represented by (8).

（式（８）中、Ｘは臭素原子、Ｒは炭素数１〜４のアルキレン基、炭素数１〜４のアルキリデン基または−ＳＯ_２−である。）
また、かかる式（８）において、好適にはＲはメチレン基、エチレン基、イソプロピリデン基、−ＳＯ_２−、特に好ましくはイソプロピリデン基を示す。

(In the formula (8), X is a bromine atom, R represents an alkylene group having 1 to 4 carbon atoms, an alkylidene group or -SO ₂ 1 to 4 carbon atoms - a.)
In the formula (8), R preferably represents a methylene group, an ethylene group, an isopropylidene group, —SO ₂ —, and particularly preferably an isopropylidene group.

  The brominated polycarbonate has a small number of remaining chloroformate groups and preferably has a terminal chlorine content of 0.3 ppm or less, more preferably 0.2 ppm or less. The amount of terminal chlorine is determined by dissolving a sample in methylene chloride, adding 4- (p-nitrobenzyl) pyridine and allowing it to react with terminal chlorine (terminal chloroformate). -3200). When the amount of terminal chlorine is 0.3 ppm or less, the thermal stability of the aromatic polycarbonate resin composition becomes better, and a resin composition excellent in light reflectivity and molding processability is provided.

The brominated polycarbonate preferably has a small number of remaining hydroxyl terminals. More specifically, the amount of terminal hydroxyl groups is preferably 0.0005 mol or less, more preferably 0.0003 mol or less with respect to 1 mol of the structural unit of brominated polycarbonate. The amount of terminal hydroxyl groups can be determined by dissolving a sample in deuterated chloroform and measuring it by ¹ H-NMR method. Such a terminal hydroxyl group amount is preferable because the thermal stability of the resin composition is further improved.

  The specific viscosity of the brominated polycarbonate is preferably in the range of 0.015 to 0.1, more preferably in the range of 0.015 to 0.08. The specific viscosity of the brominated polycarbonate is calculated according to the formula for calculating the specific viscosity used in calculating the viscosity average molecular weight of the aromatic polycarbonate resin which is the component A of the present invention.

  When the halogen-based flame retardant is blended, the blending amount is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on a total of 100 parts by weight of the component A and the component B. More preferably, it is 1 to 7 parts by weight.

(Iii-iv) Organic metal salts other than alkali (earth) metal salts of sulfonates Organic metal salts other than alkali (earth) metal salts of sulfonates include alkali (earth) metal salts of sulfate esters and aromatic sulfones. Preferred examples include alkali (earth) metal salts of amides. Examples of alkali (earth) metal salts of sulfates include alkali (earth) metal salts of sulfates of monovalent and / or polyhydric alcohols, and such monovalent and / or polyhydric alcohols. Examples of sulfuric acid esters include methyl sulfate, ethyl sulfate, lauryl sulfate, hexadecyl sulfate, polyoxyethylene alkylphenyl ether sulfate, pentaerythritol mono-, di-, tri-, tetra-sulfate, and lauric acid monoglyceride sulfate. Examples include esters, sulfates of palmitic acid monoglyceride, and sulfates of stearic acid monoglyceride. The alkali (earth) metal salts of these sulfates are preferably alkali (earth) metal salts of lauryl sulfate.

  Alkali (earth) metal salts of aromatic sulfonamides include, for example, saccharin, N- (p-tolylsulfonyl) -p-toluenesulfonimide, N- (N′-benzylaminocarbonyl) sulfanilimide, and N- ( And an alkali (earth) metal salt of phenylcarboxyl) sulfanilimide.

  The content of the organic metal salt other than the alkali (earth) sulfonate metal salt is preferably 0.001 to 1 part by weight based on the total of 100 parts by weight of the component A and the component B, more preferably 0.001. 005 to 0.5 parts by weight, more preferably 0.01 to 0.1 parts by weight.

(Iv) Optical brightener The polycarbonate resin composition of the present invention may contain a fluorescent brightener as necessary. Inclusion of a fluorescent brightening agent increases the amount of reflected light. As the optical brightener, known bisbenzoxazole, coumarin, bis (styryl) biphenyl, and the like can be used. Of these, coumarin fluorescent whitening agents are preferred. Examples of the coumarin fluorescent whitening agent include triazine-phenylcoumarin, benzotriazole-phenylcoumarin, and naphthotriazole-phenylcoumarin. For example, a fluorescent brightener represented by the following formula (9) is preferable.

（但し、上記式中Ｒ_１はアミノ基、アルキル基置換アミノ基、水酸基、および下記式（９-i）、（９-ii）または（９-iii）のいずれかを示し、Ｒ_２は水素原子またはフルオロアルキル基を示し、Ｒ_３は水素原子、アルキル基、またはアリール基のいずれかを示す。）

(In the above formula, R ₁ represents an amino group, an alkyl group-substituted amino group, a hydroxyl group, and any one of the following formulas (9-i), (9-ii) or (9-iii), and R ₂ represents hydrogen) An atom or a fluoroalkyl group, and R ₃ represents a hydrogen atom, an alkyl group, or an aryl group.)

  The content of the optical brightener is preferably 0.0001 to 1 part by weight, more preferably 0.0005 to 0.5 part by weight, still more preferably 0, based on 100 parts by weight of the total of the A component and the B component. 0.001 to 0.1 parts by weight. In such a range, better light reflectivity is achieved.

(V) Release agent The polycarbonate resin composition of the present invention may contain a release agent. Examples of the release agent include saturated fatty acid esters, unsaturated fatty acid esters, polyolefin waxes (polyethylene wax, 1-alkene polymer, etc.), silicone compounds, fluorine compounds (fluorine oil typified by polyfluoroalkyl ether, etc.). , Paraffin wax, beeswax and the like. The amount of the release agent is preferably 0.005 to 2 parts by weight, more preferably 0.01 to 0.8 parts by weight, based on the total of 100 parts by weight of the component A and the component B.

  Among such release agents, saturated fatty acid esters, particularly partial esters and / or full esters of higher fatty acids and polyhydric alcohols are preferred. Full esters are particularly preferred. Here, the higher fatty acid refers to an aliphatic carboxylic acid having 10 to 32 carbon atoms. Specific examples thereof include decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid (palmitic acid). ), Heptadecanoic acid, octadecanoic acid (stearic acid), nonadecanoic acid, icosanoic acid, docosanoic acid, hexacosanoic acid and other saturated aliphatic carboxylic acids, as well as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, eicosapentaene Mention may be made of unsaturated aliphatic carboxylic acids such as acids and cetoleic acid. Among these, the aliphatic carboxylic acid preferably has 10 to 22 carbon atoms, and more preferably has 14 to 20 carbon atoms. In particular, saturated aliphatic carboxylic acids having 14 to 20 carbon atoms, particularly stearic acid and palmitic acid are preferred. The aliphatic carboxylic acid such as stearic acid is usually a mixture containing other carboxylic acid components having different numbers of carbon atoms. Also in the saturated fatty acid ester, ester compounds obtained from stearic acid or palmitic acid which are produced from such natural fats and oils and are in the form of a mixture containing other carboxylic acid components are preferably used.

  On the other hand, as a polyhydric alcohol which is a structural unit of saturated fatty acid ester, a C3-C32 thing is more preferable. Specific examples of such polyhydric alcohols include glycerin, diglycerin, polyglycerin (for example, decaglycerin), pentaerythritol, dipentaerythritol, diethylene glycol, propylene glycol, and the like.

  The acid value in the saturated fatty acid ester of the present invention is preferably 20 or less (can take substantially 0), and the hydroxyl value is more preferably in the range of 20 to 500 (more preferably 50 to 400). Further, the iodine value is preferably 10 or less (can take substantially 0). These characteristics can be obtained by a method defined in JIS K 0070.

  The content of the release agent is 0.005 to 2 parts by weight, preferably 0.01 to 1 part by weight, preferably 0.05 to 0.5 parts, based on the total of 100 parts by weight of the component A and the component B. Parts by weight. In such a range, the resin composition achieves both good releasability and light reflectivity.

(Vi) Reinforcing filler Various known fillers can be blended in the polycarbonate resin composition of the present invention as a reinforcing filler. However, since the resin composition of the present invention is required to have a high whiteness, a silicate mineral filler or a glass filler having a high whiteness is preferable as the reinforcing filler. Examples of such silicate mineral fillers include talc, mascobite mica, synthetic fluorine mica, smectite, and wollastonite. Examples of the glass filler include glass fiber, glass flake, and glass milled fiber. As the silicate mineral filler and the glass filler, fillers whose surfaces are coated with metal oxides such as titanium oxide, zinc oxide, cerium oxide, and silicon oxide can also be used.

  The reinforcing filler may be previously surface treated with various surface treatment agents. Such surface treatment agents include silane coupling agents (including alkylalkoxysilanes and polyorganohydrogensiloxanes), higher fatty acid esters, acid compounds (for example, phosphorous acid, phosphoric acid, carboxylic acid, and carboxylic acid anhydrides). Etc.) and various surface treatment agents such as wax. Furthermore, it may be granulated with a sizing agent such as various resins, higher fatty acid esters, and waxes.

  The reinforcing filler can be blended up to 100 parts by weight based on the total of 100 parts by weight of the component A and the component B. The upper limit is preferably 25 parts by weight, more preferably 20 parts by weight. When there are too many compounding quantities of a reinforcing filler, a hue will deteriorate and light reflectivity will fall easily. Also, the loss of surface smoothness is not preferable as a light reflecting material.

(Vii) Antistatic agent The polycarbonate resin composition of the present invention may require antistatic performance, and in such a case, it is preferable to include an antistatic agent. Examples of such antistatic agents include (1) organic sulfonic acid phosphonium salts such as (1) aryl sulfonic acid phosphonium salts represented by dodecylbenzene sulfonic acid phosphonium salts, and alkyl sulfonic acid phosphonium salts, and tetrafluoroboric acid phosphonium salts. Examples thereof include phosphonium borate salts. The content of the phosphonium salt is suitably 5 parts by weight or less, preferably 0.05 to 5 parts by weight, more preferably 1 to 3.5 parts by weight, based on a total of 100 parts by weight of component A and component B. Parts, more preferably in the range of 1.5 to 3 parts by weight.

  Antistatic agents include, for example: (2) lithium organic sulfonate, organic sodium sulfonate, organic potassium sulfonate, cesium organic sulfonate, rubidium organic sulfonate, calcium organic sulfonate, magnesium organic sulfonate, and barium organic sulfonate And organic sulfonate alkali (earth) metal salts. Such metal salts are also used as flame retardants as described above. More specific examples of such metal salts include metal salts of dodecylbenzene sulfonic acid and metal salts of perfluoroalkane sulfonic acid. The content of the organic sulfonate alkali (earth) metal salt as an antistatic agent is suitably 0.5 parts by weight or less, preferably 0.001 based on the total of 100 parts by weight of the component A and the component B. It is -0.3 weight part, More preferably, it is 0.005-0.2 weight part. In particular, alkali metal salts such as potassium, cesium, and rubidium are preferable.

  Examples of the antistatic agent include (3) organic sulfonic acid ammonium salts such as alkylsulfonic acid ammonium salt and arylsulfonic acid ammonium salt. The ammonium salt is suitably 0.05 parts by weight or less based on the total of 100 parts by weight of the component A and the component B. Examples of the antistatic agent include (4) a polymer containing a poly (oxyalkylene) glycol component such as polyether ester amide as a constituent component. The polymer is suitably 5 parts by weight or less based on a total of 100 parts by weight of the component A and the component B.

(Viii) Other additives The polycarbonate resin composition of the present invention includes a thermoplastic resin other than the component A, a rubbery polymer, a light diffusing agent, a dye / pigment other than the fluorescent brightener, a flow modifier, an antibacterial agent. An agent, a dispersing agent such as liquid paraffin, a photocatalytic antifouling agent, a heat ray absorbent and a photochromic agent can be blended.

  Examples of the thermoplastic resin other than the component A include styrene resins (for example, acrylonitrile-styrene copolymer resin (AS resin), acrylonitrile-butadiene-styrene copolymer resin (ABS resin), and polystyrene resin), aromatic resins, and the like. Polyester resin (polyethylene terephthalate resin (PET resin), polybutylene terephthalate resin (PBT resin), cyclohexanedimethanol copolymerized polyethylene terephthalate resin (so-called PET-G resin), polyethylene naphthalate resin, polybutylene naphthalate resin, etc.) Polymethyl methacrylate resin (PMMA resin), cyclic polyolefin resin, polylactic acid resin, polycaprolactone resin, thermoplastic fluororesin (eg, represented by polyvinylidene fluoride resin), Olefin resins (polyethylene resins, ethylene - (alpha-olefin) copolymer resins, polypropylene resins, and propylene - (alpha-olefin) copolymer resins, etc.) are exemplified. Examples of the rubbery polymer include various core-shell type graft copolymers and thermoplastic elastomers. The thermoplastic resin and the rubbery polymer are preferably 20 parts by weight or less, more preferably 10 parts by weight or less, based on a total of 100 parts by weight of the component A and the component B. On the other hand, when the thermoplastic resin and the rubbery polymer are blended, 0.05 parts by weight or more is preferable based on the total of 100 parts by weight of the component A and the component B.

  Examples of the light diffusing agent include polymer fine particles (preferably acrylic crosslinked particles and silicone crosslinked particles having a particle diameter of several μm), low refractive index inorganic fine particles other than the reinforcing filler, and composites thereof. The content is 20 parts by weight or less, more preferably 10 parts by weight or less based on 100 parts by weight of the total of the A component and the B component. Moreover, when mix | blending a light-diffusion agent, 0.005 weight part or more is preferable on the basis of 100 weight part in total of A component and B component.

  As dyes and pigments other than the fluorescent brightening agent, so-called bluing agents are more preferably blended. In addition, various dyes can be used in accordance with the hue when the hue of the reflected light needs to be adjusted. When such a dye / pigment is used, its content is preferably 0.00001 to 0.1 parts by weight, more preferably 0.00005 to 0.05 parts by weight, based on 100 parts by weight of the total of component A and component B. It is.

<About the manufacturing method of a resin composition>
In producing the polycarbonate resin composition of the present invention, the production method is not particularly limited. However, in order to achieve good dispersion of the titanium dioxide pigment, a preferred method for producing the resin composition of the present invention is a method in which each component is melt-kneaded using a multi-screw extruder such as a twin-screw extruder.

  A typical example of the twin screw extruder is ZSK (trade name, manufactured by Werner & Pfleiderer). Specific examples of similar types include TEX (trade name, manufactured by Nippon Steel Works, Ltd.), TEM (trade name, manufactured by Toshiba Machine Co., Ltd.), KTX (product name, manufactured by Kobe Steel, Ltd.), and the like. Can be mentioned. In addition, melt kneaders such as FCM (manufactured by Farrel, trade name), Ko-Kneader (manufactured by Buss, trade name), and DSM (manufactured by Krauss-Maffei, trade name) can also be given as specific examples. Among the above, the type represented by ZSK is more preferable. In such a ZSK type twin screw extruder, the screw is a fully meshed type, and the screw includes various screw segments having different lengths and pitches, and various kneading disks having different widths (and corresponding kneading segments). It consists of

  A more preferable embodiment in the twin screw extruder is as follows. As the screw shape, one, two, and three screw screws can be used, and in particular, a two-thread screw having a wide range of application in both the ability to convey the molten resin and the shear kneading ability can be preferably used. The ratio (L / D) of the screw length (L) to the diameter (D) in the twin-screw extruder is preferably 20 to 45, more preferably 28 to 42. When L / D is large, uniform dispersion is likely to be achieved, whereas when it is too large, decomposition of the resin is likely to occur due to thermal degradation. The screw needs to have one or more kneading zones composed of kneading disk segments (or kneading segments corresponding thereto) for improving kneadability, and preferably 1 to 3 kneading zones.

  Furthermore, as an extruder, what has a vent which can deaerate the water | moisture content in a raw material and the volatile gas generate | occur | produced from melt-kneading resin can be used preferably. From the vent, a vacuum pump is preferably installed for efficiently discharging generated moisture and volatile gas to the outside of the extruder. It is also possible to remove a foreign substance from the resin composition by installing a screen for removing the foreign substance mixed in the extrusion raw material in the zone in front of the extruder die. Examples of such a screen include a wire mesh, a screen changer, a sintered metal plate (such as a disk filter), and the like.

  Furthermore, the feeding method of the component B and other additives (simply referred to as “additive” in the following examples) to the extruder is not particularly limited, but the following methods are typically exemplified. (I) A method of supplying the additive into the extruder independently of the polycarbonate resin. (Ii) A method in which the additive and the polycarbonate resin powder are premixed using a mixer such as a super mixer and then supplied to the extruder. (Iii) A method of melt-kneading an additive and a polycarbonate resin in advance to form a master pellet.

  One of the methods (ii) is a method in which all necessary raw materials are premixed and supplied to the extruder. In another method, a master agent containing a high concentration of additives is prepared, and the master agent is independently or further premixed with the remaining polycarbonate resin and then supplied to the extruder. The master agent can be selected from either a powder form or a form obtained by compressing and granulating the powder. Other premixing means include, for example, a Nauter mixer, a V-type blender, a Henschel mixer, a mechanochemical apparatus, and an extrusion mixer. A high-speed stirring type mixer such as a super mixer is preferable. Yet another premixing method is, for example, a method in which a polycarbonate resin and an additive are uniformly dispersed in a solvent and then the solvent is removed.

  The resin extruded from the extruder is directly cut into pellets, or after forming strands, the strands are cut with a pelletizer and pelletized. Furthermore, when it is necessary to reduce the influence of external dust or the like, it is preferable to clean the atmosphere around the extruder. Furthermore, in the manufacture of such pellets, various methods already proposed for polycarbonate resin for optical discs are used to narrow the shape distribution of pellets, reduce miscuts, and reduce fine powder generated during transportation or transportation. In addition, it is possible to appropriately reduce bubbles (vacuum bubbles) generated inside the strands and pellets. By these prescriptions, it is possible to increase the molding cycle and reduce the occurrence rate of defects such as silver. Moreover, although the shape of a pellet can take common shapes, such as a cylinder, a prism, and a spherical shape, it is a cylinder more suitably. The diameter of such a cylinder is preferably 1 to 5 mm, more preferably 1.5 to 4 mm, and still more preferably 2 to 3.3 mm. On the other hand, the length of the cylinder is preferably 1 to 30 mm, more preferably 2 to 5 mm, and still more preferably 2.5 to 3.5 mm.

<About a molded product comprising the resin composition of the present invention>
The polycarbonate resin composition of the present invention obtained as described above can usually produce various products by injection molding the pellets produced as described above. Furthermore, the resin melt-kneaded by an extruder can be directly made into a sheet, a film, a profile extrusion molded product, a direct blow molded product, and an injection molded product without going through pellets.

  In such injection molding, not only a normal molding method but also an injection compression molding, an injection press molding, a gas assist injection molding, a foam molding (including those by injection of a supercritical fluid), an insert molding, depending on the purpose as appropriate. A molded product can be obtained using an injection molding method such as in-mold coating molding, heat insulating mold molding, rapid heating / cooling mold molding, two-color molding, sandwich molding, and ultrahigh-speed injection molding. The advantages of these various molding methods are already widely known. In addition, either a cold runner method or a hot runner method can be selected for molding.

  Moreover, the resin composition of this invention can also be utilized in the form of various profile extrusion-molded articles, a sheet | seat, a film, etc. by extrusion molding. For forming sheets and films, an inflation method, a calendar method, a casting method, or the like can also be used. It is also possible to form a heat-shrinkable tube by applying a specific stretching operation. The resin composition of the present invention can be formed into a molded product by rotational molding, blow molding or the like.

  Thereby, a molded article of a polycarbonate resin composition having excellent light reflectance and thermal stability is provided. That is, according to the present invention, there is provided a molded product obtained by melt-molding a polycarbonate resin composition comprising 100 parts by weight in total of 60 to 99.9 parts by weight of component A and 0.1 to 40 parts by weight of component B. Is done.

  A specific example of such a molded article is a backlight reflector for a liquid crystal display device. Examples of the light source of the backlight include cold cathode fluorescent lamps and light emitting diodes (LEDs, particularly white LEDs), and are particularly suitable for white LED arrays.

  Furthermore, various surface treatments can be performed on the molded article made of the polycarbonate resin composition of the present invention. Surface treatment here refers to a new layer on the surface of resin molded products such as vapor deposition (physical vapor deposition, chemical vapor deposition, etc.), plating (electroplating, electroless plating, hot dipping, etc.), painting, coating, printing, etc. A method used for ordinary polycarbonate resin is applicable. Specific examples of the surface treatment include various surface treatments such as hard coat, water / oil repellent coat, ultraviolet absorption coat, infrared absorption coat, and metalizing (evaporation).

  Since the polycarbonate resin composition of the present invention has excellent light reflectance and thermal stability, it is suitably used for various light reflecting materials. More specifically, various lamp reflectors can be mentioned, for example, reflectors for illumination lamps such as fluorescent lamps, backlight reflectors for various display devices such as liquid crystal display devices, reflectors for switches, and reflectors for LED arrays. In addition, a reflecting plate in which these functions are combined is exemplified. That is, the polycarbonate resin composition of the present invention is useful for various applications such as various electronic / electrical equipment, OA equipment, vehicle parts, machine parts, other agricultural materials, transport containers, playground equipment, and miscellaneous goods. The effect is exceptional.

  The form of the present invention considered to be the best by the present inventor is a collection of the preferable ranges of the above requirements. For example, typical examples are described in the following examples. Of course, the present invention is not limited to these forms.

The following examples further illustrate the present invention. The evaluation was based on the following method.
(1) Light reflectance: A 2 mm thick molded plate (90 mm long × 50 mm wide) having an arithmetic average roughness (Ra) of 0.03 μm obtained by injection molding, and a color computer (TC manufactured by Tokyo Denshoku TC) -1800MK-II). Evaluation was made with the lowest reflectance value at wavelengths of 450 nm to 850 nm.
(2) Thermal stability:
(I) Measurement of molecular weight reduction (ΔMv) The obtained pellets were dried with a hot air dryer at 120 ° C. for 6 hours, and then cylinder temperature 270 using an injection molding machine (Sumitomo Heavy Industries, Ltd. SG-150U). A molded article including a tensile test piece was prepared at a temperature of 70 ° C and a mold temperature of 70 ° C. After 20-shot continuous molding of the molded product, the injection cylinder was retracted in a state where the measurement was completed, and the molten resin was allowed to stay in the cylinder for 5 minutes. After such residence, molding of 4 shots was again performed under the same conditions. A molded product of the resin composition retained in the cylinder was produced by such molding. Among them, the viscosity average molecular weight of the molded product of the second shot was measured by the method described in the text. On the other hand, the viscosity average molecular weight of the molded product of the 20th shot before residence was also measured in the same manner. A value obtained by subtracting the molecular weight after residence from the molecular weight before residence was evaluated as ΔMv. It can be said that the smaller the ΔMv, the better the thermal stability.
(Ii) Appearance evaluation:
A 2 mm thick molded plate (length 90 mm × width 50 mm) having an arithmetic average roughness (Ra) of 0.03 μm obtained by injection molding was molded, and the hue and silver streak were observed. In the evaluation, the 10th shot immediately after the purge was discarded, the 11th shot was used for hue evaluation, and the molded product up to 20th shot was then used for silver streak evaluation. Hue was measured by using a color computer (TC-1800MK-II: manufactured by Tokyo Denshoku Co., Ltd.) to measure the L value in the portion of the molded plate having a thickness of 2 mm where the arithmetic average roughness (Ra) was 0.03 μm. did. In addition, the case where all silver streaks occurred was evaluated as x, the case where the silver streak occurred once was evaluated as Δ, and the case where it did not occur was evaluated as ○. In addition, since the brightness increases as the L value increases, the molded product has a stronger white feeling in visual observation. Therefore, in such evaluation, the larger the L value, the better.

[Examples 1 to 13 and Comparative Examples 1 to 6]
Various additives listed in Tables 1 to 3 were mixed in polycarbonate resin powder produced from bisphenol A and phosgene by the interfacial polycondensation method, and mixed in a blender. Nippon Steel Works Co., Ltd .: TEX30α (completely meshing, rotating in the same direction, two-thread screw) was melt kneaded to obtain pellets. Additives other than the titanium dioxide pigment were previously prepared in advance using a Henschel mixer at a concentration of 10 times the blending amount, and the whole was mixed by a blender. The extrusion conditions were a discharge rate of 20 kg / h, a screw rotation speed of 150 rpm, a vent vacuum of 3 kPa, and an extrusion temperature of 260 ° C. from the first supply port to the die part.

  After drying the obtained pellets at 120 ° C. for 6 hours in a hot air circulating dryer, using an injection molding machine, the cylinder temperature was 270 ° C., the mold temperature was 70 ° C., and the firing speed was 50 mm / sec. A smooth flat test piece having a length of 90 mm, a width of 50 mm, a thickness of 2 mm, and a surface arithmetic average roughness (Ra) of 0.03 μm was molded. An injection molding machine (Sumitomo Heavy Industries, Ltd .: SG-150U) was used. Each evaluation result of the obtained shaping | molding board was shown to Tables 1-3.

In addition, the content of each component indicated by symbols in Tables 1 to 3 is as follows.
(A component)
PC-1: Linear aromatic polycarbonate resin powder synthesized by interfacial polycondensation from bisphenol A, p-tert-butylphenol as a terminal terminator, and phosgene (manufactured by Teijin Chemicals Ltd .: Panlite L-1225WX (product) Name), viscosity average molecular weight 19,700)
PC-2: Linear aromatic polycarbonate resin powder synthesized by interfacial polycondensation from bisphenol A, p-tert-butylphenol as a terminal terminator, and phosgene (manufactured by Teijin Chemicals Ltd .: CM-1000 (trade name)) , Viscosity average molecular weight 16,000)

(B component)
B-1: Titanium dioxide (White DCF-T-17007, manufactured by Resino Color Industry Co., Ltd.) The titanium dioxide reduced the weight loss at 23 ° C to 100 ° C by a thermogravimetric apparatus (TGA) (a) wt% and 23 ° C (B)-(a) is 0.28 when the weight loss at 300 ° C. is (%) by weight, and the weight ratio of Al element / Ti element in the fluorescent X-ray measurement is 0.008, and Si element / Titanium dioxide pigment having a weight ratio of Ti element of 0.009)
In addition, the calculation of the weight ratio of each element in the fluorescent X-ray measurement was performed by the basic parameter method using MESA-500 type manufactured by Horiba, Ltd. This calculation method is the same for other titanium dioxide pigments.
B-2: Titanium dioxide (this titanium dioxide is the same TiO ₂ raw material and surface treatment agent as Ishihara Sangyo Co., Ltd. Typaque PC-3 (trade name), and the amount of the surface treatment agent is changed to a thermogravimetric apparatus ( (B)-(a) is 0.24 when the weight loss at 23 ° C. to 100 ° C. by TGA) is (a) wt% and the weight loss at 23 ° C. to 300 ° C. is (b) wt%, and fluorescence (Titanium dioxide pigment adjusted so that the weight ratio of Al element / Ti element in X-ray measurement is 0.006 and the weight ratio of Si element / Ti element is 0.019)
(For comparison of B component)
B-3: Titanium dioxide (Ishihara Sangyo Co., Ltd. Typek PC-3 (trade name), the titanium dioxide is (a) wt% weight loss at 23 ° C. to 100 ° C. by a thermogravimetric apparatus (TGA), and Weight reduction at 23 ° C. to 300 ° C. (b) (b)-(a) is 0.57 when weight%, and Al element / Ti element weight ratio in the fluorescent X-ray measurement is 0.014, and (It is a titanium dioxide pigment having a weight ratio of Si element / Ti element of 0.018)
B-4: Titanium dioxide (this titanium dioxide is the same TiO ₂ raw material and surface treatment agent as Ishihara Sangyo Co., Ltd. Typaque PC-3 (trade name), and the amount of the surface treatment agent is changed to a thermogravimetric apparatus ( (B)-(a) is 0.50 when the weight loss from 23 ° C. to 100 ° C. by TGA) is (a) wt% and the weight loss from 23 ° C. to 300 ° C. is (b) wt%, and (This is a titanium dioxide pigment adjusted so that the weight ratio of Al element / Ti element in the fluorescent X-ray measurement is 0.006 and the weight ratio of Si element / Ti element is 0.023)
B-5: Titanium dioxide (this titanium dioxide is the same TiO ₂ raw material and surface treatment agent as DCF-T-17007 manufactured by Resino Color Industry Co., Ltd.), and the amount of the surface treatment agent is 23 by a thermogravimetric apparatus (TGA). (B)-(a) is 1.38 when the weight loss at 100 ° C. to 100 ° C. is (a) wt% and the weight loss at 23 ° C. to 300 ° C. is (b) wt%, and X-ray fluorescence measurement (Titanium dioxide pigment adjusted so that the weight ratio of Al element / Ti element is 0.005 and the weight ratio of Si element / Ti element is 0.008)

(C component)
C-1: Perfluorobutanesulfonic acid potassium salt (Megafac F-114P, manufactured by Dainippon Ink and Chemicals, Inc.)
(D component)
D-1: Polytetrafluoroethylene having a fibril-forming ability (polyflon MPA FA500 manufactured by Daikin Industries, Ltd.)
D-2: A mixture of polytetrafluoroethylene particles having fibril-forming ability and styrene-acrylonitrile copolymer particles (polytetrafluoroethylene content 50% by weight) (BLENDEX 449 manufactured by GE Specialty Chemical Co., Ltd.).
(Other)
HP: hindered phenol antioxidant (Ciba Specialty Chemicals: Irganox 1076)
VP: Full ester having a molecular weight of 1061 composed of pentaerythritol and an aliphatic carboxylic acid (manufactured by Cognis Japan Co., Ltd .: Roxyol VPG-861)
CE: Cyclic imino ester ultraviolet absorber (Takemoto Yushi Co., Ltd .: CEi-P)
PSR: Coumarin-based optical brightener (manufactured by Hakkol Chemical Co., Ltd .: Hakkor PSR-B (trade name))

  As is apparent from Tables 1 to 3, it can be seen that the polycarbonate resin composition of the present invention has excellent light reflectivity and thermal stability. That is, it can be seen that the resin composition has characteristics suitable for a light reflecting material.

(Example 14)
Using the pellets obtained in Example 2, a light reflector for an LED array type backlight having a bottomed lattice shape having a length of 6 cm and a width of 4 cm shown in FIG. A liquid crystal display was created by molding according to a molding machine and temperature conditions, mounting a white LED on each block to create a backlight, and replacing the backlight unit of a liquid crystal display used for a mobile phone. The visually recognized image was highly sharp.

(Example 15)
Using the pellets obtained in Example 8, a backlight was produced in the same manner as in Example 14, and the image visually recognized was a liquid crystal display with a sharper impression than in Example 14. was gotten.

  The present invention provides a polycarbonate resin composition suitable for a light reflecting material. However, other than that, it is also possible to utilize the semiconductor property of the titanium dioxide pigment as a dielectric material and a livestock heat material.

It is a perspective schematic diagram which shows the light reflection board for LED array type backlights produced in the Example.

Explanation of symbols

1 Light reflector main body (length 60mm, width 40mm, height 4mm)
2 Each LED block (depth 2.5mm, the inner periphery of the recess is mirror-finished)
3 LED fixing recess

Claims (5)

0.0001 to 1 part by weight of a coumarin-based fluorescent brightener for 100 parts by weight in total of 60 to 99.9 parts by weight of a polycarbonate resin (component A) and 0.1 to 40 parts by weight of a titanium dioxide pigment (component B) . The titanium dioxide pigment is a resin composition containing no parts and no silicone compound , wherein the titanium dioxide pigment is (i) a weight loss from 23 ° C. to 100 ° C. by thermogravimetric analysis (TGA), (a) wt%, When the weight loss at 23 ° C. to 300 ° C. is (b) wt%, 0.05 ≦ (b) − (a) ≦ 0.6 is satisfied, (ii) Ti element in the fluorescent X-ray measurement, Al When the weight ratio derived from the element and Si element is (c) wt%, (d) wt%, and (e) wt%, respectively, 0.001 ≦ (d) / (c) ≦ 0.01 is satisfied And 0.001 ≦ (e) / ( ) Satisfy ≦ 0.02 polycarbonate resin composition which is a titanium dioxide pigment.   2. The polycarbonate resin composition according to claim 1, further comprising 0.0001 to 2 parts by weight of an alkali (earth) metal salt (component C) based on a total of 100 parts by weight of component A and component B. 3. .   3. The fluorinated polymer (component D) having 0.05 to 1 part by weight further having a fibril-forming ability, based on a total of 100 parts by weight of the component A and the component B. The polycarbonate resin composition according to item.   The ratio of A component and B component is 70-90 weight part of A component, and 10-30 weight part of B component, The polycarbonate resin composition of any one of Claims 1-3.   The light reflection material formed from the polycarbonate resin composition of any one of the said Claims 1-4.

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